1. Field of the Invention
The present invention relates to a printing apparatus and to a control method therefor, and relates more specifically to a method for handling maintenance information in a printing apparatus that is part of a point-of-sale (POS) system or other financial transaction system.
2. Description of the Related Art
A conventional printing apparatus, hereafter simply xe2x80x9cprinterxe2x80x9d, typically stores an operating history of the printer in an EEPROM (electrically erasable programmable ROM), flash ROM, or other type of nonvolatile storage. This operating history typically represents the total number of operating hours, the number of characters printed, or some other measure(s) that can be used as a guide to determine when maintenance is required. When the printer is turned on and initialized, this operating history is usually downloaded from the nonvolatile memory to volatile memory such as RAM. The operating history is thus updated in RAM during printer operation, and written back to the nonvolatile memory as part of a shutdown procedure when the power is turned off, or at some regular interval, such as at a constant time interval or when some specified value is reached.
The operating history can also be read, displayed or printed in response to a command from a host device or operator command for user confirmation.
Japan Unexamined Patent Publication (kokai) H6-3956 (1994-3956) discloses a method for resetting historical data and starting the counter for a particular part when a part is replaced.
Japan Unexamined Patent Publication (kokai) H4-305657 (1992-305657) also discloses a method for redundantly storing historical data to a plurality of memory devices, thereby avoiding the problem of maintenance history data being lost as a result of a memory error or similar problem.
A problem with a printer as noted above is that usage of individual parts cannot be specifically determined from the total operating time of the printer. For example, assuming the same total operating time, use of the print head and paper transportation mechanism differ when printing only a few characters on many lines and when printing many characters on only a few lines. As a result, it is not possible to accurately determine a part""s wear from the total operating time.
Furthermore, historical data such as the number of characters printed is typically reset when a part""s useful life is exhausted and the part(s) is replaced based on this data. This makes it impossible to determine the total operating time or total operating count of other mechanical parts used to drive the parts that were replaced.
Total operating count information makes it possible to determine how much a product is actually used by the end user, and is effective for quality assurance and troubleshooting purposes.
This information can also be taken into consideration in the development of new products to help the manufacturer provide products with desirable specifications.
Therefore, it is an object of the present invention to overcome the aforementioned problems.
An object of the present invention is to provide a printing apparatus that can store total operating information for individual parts and components of the printing apparatus.
A further object of the present invention is to provide a printing apparatus capable of separately storing historical data related to user-replaceable consumables, and historical data related to parts that are not replaceable by the user, including parts and assemblies for driving other parts.
To achieve the above objects, a printing apparatus according to the present invention comprises: a nonvolatile storage for holding stored content even when power is not supplied to the printing apparatus; an operation counter for counting a, value indicative of a printing apparatus operation; an operation counter storage for storing a historical operation count of the printing apparatus based on a value counted by the operation counter, and a processor for writing an interim count value and a cumulative count value to the nonvolatile storage.
Specific printer operations, such as the number of characters printed, distance of recording medium transportation, and the number of times the automatic paper cutter is operated, can be individually accumulated, and the historical counts, that is, the cumulative counts since the printer was first used, can be stored in memory.
The nonvolatile storage or memory preferably comprises a plurality of areas for storing a respective plurality of historical operation counts such that count values from the operation counter storage can be written to each of the plurality of areas to store historical operation count values for a plurality of printer operations, and to store both interim and cumulative counts for each operation.
This configuration enables the cumulative operations counts to be it maintained even after a part or component has been replaced and its associated interim count has been reset.
The printing apparatus preferably further comprises a timer for measuring an operating time period of the printing apparatus; and an evaluation unit for determining whether the printing apparatus is performing a specific process. In this configuration the evaluation unit determines whether the specific process is in progress following expiration of the measured operating time period, and the historical count stored in the operation counter storage is written to the nonvolatile storage when the evaluation unit determines that the specific process is not in progress.
This configuration makes it possible to reduce the count information that is lost when the power is interrupted, for example. Printer operations are also not disrupted because writing data to the nonvolatile memory is prohibited during certain printer operations, including actual printing and data processing operations.
The count data stored in the operation counter storage further is preferably written to the nonvolatile storage when the evaluation unit determines that the specific process is not in progress, or when the evaluation unit determines that the specific process is in progress but the timer measures a second time period, which is longer than the operating time period, has elapsed.
By thus forcing writing to nonvolatile memory when a specific printer operation takes a long time, it is possible to avoid the situation where data is not stored for an extended period of time. As a result, it is also possible to reduce the count information that is lost when the power is interrupted, for example.
A printing apparatus according to the present invention yet further preferably comprises an operation count changing unit for changing a historical operation count stored in the nonvolatile storage based on a specific command received from a host device, and prohibiting changing a historical operation count stored in one area of the plurality of areas.
Memory can therefore be divided into an area that includes an interim count that can be reset when a part is replaced, and an area that includes a cumulative count that cannot be reset. As a result, accurate historical information can be maintained when there are parts that are replaced at different times, based on a cumulative count corresponding to the replaced part.
A printing apparatus according to the present invention yet further preferably comprises an operation count transmission unit for reading and sending to the host device a historical operation count stored in the nonvolatile storage based on a specific command received from the host device; and an operation count conversion unit for converting a historical operation count to an index enabling service life evaluation. In this configuration the operation count transmission unit sends the converted service life evaluation index obtained from the operation count conversion unit when sending a historical operation count to the host device.
The host device can thus obtain count values in a form enabling easier determination of component service life, which is particularly useful when service life is a function of both component operation and frequency of operation.
Yet further preferably, this printing apparatus comprises data conversion for coding the historical operation count or converted service life evaluation index obtained from the operation count conversion means. In this case, the operation count transmission unit sends the coded data to the host device. As a result, data can be sent reliably to the host device even when certain data cannot be transmitted due to interface limitations.
Yet further preferably, this printing apparatus comprises a display for displaying the service life evaluation index obtained by the operation count, conversion unit, and/or the historical operation count stored in the nonvolatile storage. The service life evaluation index obtained by the operation count; conversion unit, and/or the historical operation count stored in the nonvolatile storage can also be printed.
The operator can therefore also obtain the count information at the printer and take whatever maintenance steps may be required.
The operation count can alternatively be written to the nonvolatile storage irrespective of the operating time measurement in response to a specific command received from the host device. Data can therefore be stored at an appropriate timing to reduce the counter information that is lost when the power is interrupted, for example.
The present invention can also be provided as a control method for a printing apparatus with the same benefits and effects described above.
The control method of the present invention can also be provided as a control program that can be executed by a control device, and can be provided on a recording medium for storing this control program. Usable recording media include Compact Disc-ROM (CD-ROM) media, floppy disks, hard disks, magneto-optical discs, various digital versatile disc (DVD) formats, including DVD-ROM, as well as magnetic tape. Furthermore, these recording media can be used to provide the program of the invention to existing printing apparatuses. In addition, the program of the invention can be made available for delivery via a network such as the World Wide Web, including directly from a Web site, for downloading to an existing printer apparatus.
Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.